Harvest Moon is like how it says its mainly about Harvesting and living a country side life more than anything. You farm, take care of animals(which you buy also), find a girl you like and get close to her(there are 3girls you choose from), you fish, mine, and a whole lot of other stuff. Its very enjoyable and relaxing to play and honestly you can get very into it lol.(At least I did hahaha) Its a lot about timing also since you gotta remember how long it takes for stuff to grow, remember to feed the animals regularly, and keep track of the girl you like. If you're planning on getting it. I highly recommend it =].
There is also a second game of it if I ain't mistaken. I didn't play it, but wanted to.